A variety of pressure vessels (including vacuum vessels) are known in the prior art which require a closure device for access. For example, such equipment includes gas filters, filter separators, gas scrubbers, pipeline scrappers, launchers and receivers, meter approvers, access openings to pressure vessels, liquid phase separators and coalescers, and the like. Such pressure vessels are often used, for example, in the oil and gas industry where it can be readily appreciated that substantial pressure loads on the order of several hundred PSIG can be generated. Equipment of the above type often features an ASME and/or API quick opening closure for access to the vessel and equipment interior.
For example, examples of quick opening type closures include U.S. Pat. No. 6,439,415 assigned to the present assignee, Perry Equipment Corporation and U.K. Patent No. GB 2172956. These patents show a closure for an equipment sub which includes a cylindrical aperture that is closed by a circular closure door member having an O ring seal. The quick opening type closures in these patents include a centralized drive hub that carries a plurality of wedge-shaped segments that are adapted to engage the equipment sub shell and thereby hold the closure head door in the closed position.
Another type of quick opening closure is a yoke-type quick opening closure as shown, for example, in a brochure entitled “Quick Opening Closures”, published by the present assignee, Perry Equipment Corporation, with a date indicated of April 2006. In this type of a closure, the yoke comprises two piece yoke sections that engage the closure head and the sub shell and in which a drawbolt can be driven to engage or disengage the yoke from the closure head that can then be swung open. The safety bolt is provided in the event that the drawbolt fails. As shown therein, some of these quick opening closures include two sets of drawbolts approximate top and bottom ends of the individual yoke segments whereas other devices include two yoke segments in which one end may be joined by a hinge. The patents and publications listed above are hereby incorporated by reference in their entireties, as these patents and publications generally disclose the present state of the art.
The present invention pertains to improvements over the state of art.